IND UCTI VE COORDINA TION 



99 



b. The importance, particularly under joint-use conditions, 

 of noise directly induced into the metallic circuit of open- 

 wire telephone pairs and the importance, therefore, of 

 suitable telephone circuit transpositions. 



Figure 5 shows exposure conditions such as may be encountered in a 

 small community serving a nearby rural area and Table V shows the 

 noise conditions at several locations during heavy power loads. 



TO LOADS 

 75KVA- PHASE A 

 90 KVA- PHASE 

 60 KVA- PHASE 

 45 KVA -3 PHASE 



A PHASE 

 WIRE 



— LEGEND — 

 3- PHASE PORTION OF FEEDER 

 2-PHASE PORTION OF FEEDER 

 I -PHASE PORTION OF FEEDER 

 UNDERGROUND TELEPHONE CABLE 

 AERIAL TELEPHONE CABLE 



•\Ar« "DROP"WIRE TO SUBSCRIBER'S 



STATION 

 — ^^ PROTECTED TERMINAL FEEDING 

 OPEN-WIRE TELEPHONE PLANT 

 SERVICE TRANSFORMER— KVA 

 AS INDICATED 

 ALL SECTIONS NOT SPECIFICALLY INDI- 

 CATED ARE AT JOINT-USE SEPARATIONS 

 WITH POLE-HEAD CONFtGURATIONS AS 

 SHOWN IN TYPICAL LAYOUTS 



APPROXIMATE 

 SCALE IN FEET 



Fig. 5 — Example of exposure conditions between 2300/4000-volt distribution feeder 

 and exchange telephone plant in suburban and rural area. 



